Functions of portable telephones have been increased, for instance, camera modules are mounted on the portable telephones. In such portable telephones, the number of keys is increased. Originally, keys are only for such function of entering telephone numbers of communication opponent parties so as to establish telephone callings. However, nowadays, not only numeric keys and a telephone calling key, but also various sorts of keys have been additionally provided.
In a patent publication 1, as one example for responding to increase in a total number of keys, such a foldable portable telephone is disclosed. In the portable telephone, keys are provided on side faces thereof, which are exposed in a closed sate where a housing of the folding type portable telephone is closed.
Patent Publication 1: JP-A-2002-204298